Create a function that counts the number of blocks of two or more adjacent 1s in an array.

Examples

count_ones([1, 0, 0, 1, 1, 0, 1, 1, 1]) ➞ 2 
# Two instances: [1, 1] (middle) and [1, 1, 1] (end)

count_ones([1, 0, 1, 0, 1, 0, 1, 0]) ➞ 0

count_ones([1, 1, 1, 1, 0, 0, 0, 0]) ➞ 1

count_ones([0, 0, 0]) ➞ 0

Notes

• A single 1 by itself (surrounded by a zero on its left and right), does not count towards the total (see first example).
• Each input will contain only zeroes and ones.